Typically, when a vehicle drives in urban areas, the vehicle may stop at an intersection, at a crossing, and the like. In such a case, if the engine is kept idled, the fuel is wasted, and the fuel consumption is increased.
Therefore, there is an automatic stopping/restarting apparatus, which automatically stops the engine of the vehicle even during driving, cuts the fuel consumption during the temporary stop of the vehicle when a condition of stop of the engine is met, and automatically restarts the engine afterwards when a predetermined condition is met during the vehicle is stopped.
In restarting the engine, a pinion gear, which transmits power of a starter to the engine in order to crank the engine, is pushed by a solenoid coil, and the pinion gear is engaged with a ring gear coupled with an engine cranking shaft, so that the engine is cranked and restarted with the power of the starter.
Here, in the engine automatic stopping/restarting apparatus, when a quick restart is requested, prompt restart of the engine is required responding to the restart request of the driver.
However, in the above-described vehicle engine automatic stopping/restarting apparatus, typically, the pinion gear is pushed and is engaged with the ring gear after the engine rotation goes into a stopped state, and even if a restart request occurs during a drop of the engine rotation in the process of a stop of the engine, restart cannot be performed until the engine rotation goes into the stopped state, and therefore, a time delay occurs by the restart is performed.
Therefore, PLT 1 discloses a technology wherein, when a restart request occurs during a drop of the engine rotation in the process of a stop of the engine, the starter is energized to idle the pinion gear, rotation speeds of the pinion gear and the ring gear are respectively detected, and the pinion gear is pushed to be engaged with the ring gear at a timing when the rotation speeds of the pinion gear and the ring gear are synchronized with each other, and the engine is promptly restarted.